The Potential of Freeform Construction Processes

The level of automation technology and processes control found in modern day construction lags significantly behind other industries such as automotive and aerospace. The construction industry has health and safety issues and still uses traditional methods of procurement. These problems are compounded by diminishing skills in the labour force. Methods of production must change if these issues are to be resolved and Freeform Construction is a collection of processes that could have potential impact. This paper outlines some of the major issues facing construction and sets a context with examples of digital fabrication in construction. Freeform Construction is defined and potential applications are presented and related to application scale. The viability of two potential applications are investigated in terms of cost.Mechanical Engineerin

Techno-economic projections for advanced small solar thermal electric power plants to years 1990-2000

Advanced technologies applicable to solar thermal electric power systems in the 1990-200 time-frame are delineated for power applications that fulfill a wide spectrum of small power needs with primary emphasis on power ratings less than 10MWe. Projections of power system characteristics (energy and capital costs as a function of capacity factor) are made based on development of identified promising technologies and are used as the basis for comparing technology development options and combinations of these options to determine developmental directions offering potential for significant improvements. Stirling engines, Brayton/Rankine combined cycles and storage/transport concepts encompassing liquid metals, and reversible-reaction chemical systems are considered for two-axis tracking systems such as the central receiver or power tower concept and distributed parabolic dish receivers which can provide efficient low-cost solar energy collection while achieving high temperatures for efficient energy conversion. Pursuit of advanced technology across a broad front can result in post-1985 solar thermal systems having the potential of approaching the goal of competitiveness with conventional power systems

Depth estimation of inner wall defects by means of infrared thermography

There two common methods dealing with interpreting data from infrared thermography: qualitatively and quantitatively. On a certain condition, the first method would be sufficient, but for an accurate interpretation, one should undergo the second one. This report proposes a method to estimate the defect depth quantitatively at an inner wall of petrochemical furnace wall. Finite element method (FEM) is used to model multilayer walls and to simulate temperature distribution due to the existence of the defect. Five informative parameters are proposed for depth estimation purpose. These parameters are the maximum temperature over the defect area (Tmax-def), the average temperature at the right edge of the defect (Tavg-right), the average temperature at the left edge of the defect (Tavg-left), the average temperature at the top edge of the defect (Tavg-top), and the average temperature over the sound area (Tavg-so). Artificial Neural Network (ANN) was trained with these parameters for estimating the defect depth. Two ANN architectures, Multi Layer Perceptron (MLP) and Radial Basis Function (RBF) network were trained for various defect depths. ANNs were used to estimate the controlled and testing data. The result shows that 100% accuracy of depth estimation was achieved for the controlled data. For the testing data, the accuracy was above 90% for the MLP network and above 80% for the RBF network. The results showed that the proposed informative parameters are useful for the estimation of defect depth and it is also clear that ANN can be used for quantitative interpretation of thermography data

Life cycle assessment of white roof and sedum-tray garden roof for office buildings in China

White roof (WR) and Sedum lineare tray garden roof (STGR) have been convinced to improve the energy-efficiency and provide various benefits for conventional impervious grey roofs. Some national and local standards have standardized and recommended these technologies in existing building retrofits, however, they do not include assessment and choice of a particular roof retrofit in different climates. This paper presents a 40-year life-cycle cost analysis (LCCA) of an office building roof retrofitted by adding either WR or STGR over an existing grey roof in five cities, located in four Chinese climate zones. The LCCA find that the WR retrofits exhibit positive life-cycle net savings (NS) in warm winter zones, ranging 5.7–35.1 CNY/m 2 , and STGR retrofits have negative NS of -81.3– -16.7 CNY/m 2 in all climate zones. The NS of both WR and STGR generally tend to improve as one moves from the coldest cities to the warmest cities. LCCA results suggest that adding new building codes concerning crediting or prescribing WR and STGR retrofits into office buildings with grey roofs in hot summer climate zones and warm winter zone in China, respectively. And featured by more specific requirements, the localized Technical Norms help promote the implementation of new building codes

Improving the thermal comfort of industrial building using insulation materials

industrial buildings are one of the larges used t worldwide, and every day it grows noticeably in many different forms of projects so , the introduction of insulation materials was very essential, and their development for enhancing a variety of parameters such as thermal comfort inside the building which became one of the very important aspects in industrial buildings. Design of any industrial building should be to the lowest cost keeping in consideration importance of thermal comfort and its contribution in the productivity improvement of the workers as well as the administrative employee as well as reducing the high costs of electricity bills that is consumed by the air-conditioning systems. And for these reasons, building materials have been improving to enhance thermal comfort inside the buildings and many insulation materials were introduced to contribute with that as well. One of these insulation materials is hemp and in fact, many associates consider it the best insulation building material ever made for its properties. Hemp comes from the hemp plant and hemp wool can be produced from the strong fibers of this plant. Hemp can be shaped in the form of blankets or boards, and both are used as environmentally friendly insulation materials. The positive part about this plant is that it can grow fast and on any type of soil worldwide. In 3 months of time, a hemp plant can reach to 4 meters, taking in a huge amount of CO2 that helps as well in purifying the air

"Matrix Exponential Stochastic Volatility with Cross Leverage"

This paper examines the economic impact of re-invention - the degree to which an innovation is modified by user - on industry growth and productivity. The paper focuses on two re-inventions made by a Japanese steel company; these inventions improved the productive efficiency of Austrian-made refining technology, namely, basic oxygen furnace (BOF). Results obtained from the plant-level production-function estimation indicate that re-inventions account for approximately 30 percent of the total factor productivity of the BOF, substantially promoting the dissemination of the BOF technology. Our simulation analysis indeed reveals that re-inventions contributed to steel output growth by about 14 percent. This paper also documents that innovating companies played the role of a "lead user" in developing and disseminating their re-invented technologies.

Post-Earthquake Home Reconstruction in the Surrounding Hills of Kathmandu Valley, Nepal, PRP 200

In April of 2015, a 7.6 magnitude earthquake struck the Kathmandu Valley at the center of Nepal. Within the following year, Kathmandu was struck by a 7.3 magnitude earthquake and multiple aftershocks. The initial earthquake caused the deaths of 8,856 people, injured 22,309, and affected eight million more. Many agencies around the world came together to fund reconstruction efforts as part of a Nepal and a Multi-Donor Trust Fund (MDTF). The MDTF conducted an Earthquake Housing Damage and Characteristics Survey (EHDC) which led to the creation of Nepal Rural Housing Reconstruction Program (NRHRP), which sought to reconstruct earthquake-resistant homes. The NRHRP developed a homeowner-driven grant process and established the National Reconstruction Authority (NRA) to distribute housing reconstruction grants to families. Those grants were to be paid out via three tranches, each after the completion of a specific construction phase. During 2017, an international collaborative effort began among four parties: Hiroshima University (HU); Tribhuvan University (TU); Nepal’s Alternative Energy Promotion Center (AEPC); and the Lyndon B. Johnson School of Public Affairs (LBJ) of the University of Texas at Austin (UT). The team investigated the challenges and opportunities for reconstruction of homes in rural areas damaged by the 2015 earthquake in and around the hinterland of Kathmandu Valley, Nepal. Within the context of a university course, students began by studying alternative building technologies (ABTs) being implemented in Nepal by local nongovernmental organizations (NGOs). When project members visited Nepal in March 2017, they interviewed rural residents to identify barriers to home reconstruction. During a field study, the students also met with local governmental officials and NGO representatives. This report describes students’ field investigation in Nepal, background research on alternative building technologies (ABTs) for home reconstruction, and recommendations developed from consultation with stakeholders and technical advisors. The first chapter starts with the earthquake and its associated damage and describes the response of the Government of Nepal (GON) and the international community in forming the MDTF, the NRHRP, and the NRA. The second chapter discusses different alternative building technologies (ABTs) considered by the GON, including bamboo, hempcrete, rammed earth, Compressed Stabilized Earth Brick (CSEB), earthbags, and modified conventional housing. Each section describes the type of building style, its construction, materials and labor required, estimates of construction time (if available), costs, and a brief section on comparative advantages and disadvantages. The third chapter describes the 2017 field study in Nepal, included the locations of the field study and interviews and discussions with local NGOs, the governmental agencies, and local residents. The research group sought to learn whether a lack of affordable and appropriate building methods could explain why many villagers still live in temporary shelters. Village residents discussed barriers to housing reconstruction unrelated to the type of home being built. The final chapter presents conclusions from 2017 field study observations of the three villages. Researchers found four common barriers to reconstruction: the cost of transportation and materials; insufficient reconstruction incentives; grant processes with many procedural barriers to funding; and the need for consistent interaction of the community with governmental agencies. One suggestion is to evaluate the home reconstruction program to assess its procedures and outcomes. A second suggestion is for Nepal to enhance the number and authority of mobile teams of professionals to assist villagers seeking to reconstruct homes.Public Affair

CFD analysis of co-firing of coke and biomass in a parallel flow regenerative lime kiln

The lime industry is a highly energy intensive industry, with a huge presence worldwide. To reduce both production costs and pollutants emissions, some lime production plants are introducing more environmentally-friendly energy sources, such as local agro-industry residues. In this paper, a numerical tool is presented, which simulates a large-scale Parallel Flow Regenerative (PFR) kiln that currently uses coke as main fuel. The developed tool aims at investigating the combustion process under conditions of co-firing of coke and biomass and to assist the plant operators in the optimization of such operating conditions. To achieve this goal, a two-way coupling Euler–Lagrange approach is used to model the dynamics of the particulate phase and their interaction with the gas phase. Pyrolysis, volatiles oxidation and char oxidation are modelled by kinetics/diffusion-limited model (for heterogeneous reactions) and mixture fraction approach (for homogeneous reactions). Moreover, two methods are investigated for representing the limestone bed: a porous medium (PM) approach and a “solid blocks” (BM) tridimensional mesh. Comparison of the results for the case of 100% coke showed that the ideal “blocks” method is more accurate as it adequately simulates the scattering of fuel particles through the PFR kiln anchor, which is limited with the PM approach. Moreover, the temperature profile, maximum and minimum temperatures, as well as CO2 and O2 concentrations at outlet, are comprised in the expected range for this technology, according to available literature. Finally, the predicted results of a co-firing case with 60% biomass (in mass) were validated with measurements in an industrial facility, with production capacity of 440 calcium oxide tons per day. The results suggest that the model is fairly accurate to predict gas temperature, as well as O2 and NOX concentrations at the kiln outlet. Although some improvements are recommended to refine the CFD predictions, these promising results and the high computational efficiency laid the foundation for future modelling of co-firing of coke and biomass, as well as the modelling of the lime calcination process. It also paves the way for facilitating the reduction of pollutant emissions thus contributing to a more sustainable lime production

Energy recovery systems based on high temperature phase change materials

Energy recovery from the waste heat released by industrial processes represents one of the greatest opportunity to reduce the consumption of primary energy and the related emission of greenhouse gases. Nevertheless, the fluctuating and/or intermittent nature of many energy-intensive processes (e.g. electric arc furnace in steel industry) hinders the deployment of current energy recovery systems. Thus, the development of technologies able to minimize the thermal power fluctuations released by such processes is required to enable the deployment of affordable energy recovery systems. With the aim of developing such type of technology, this thesis explores the potential of latent heat storage systems based on phase change materials (PCMs) to minimize the thermal power fluctuations of high-temperature waste heat sources. In particular, three significant areas of investigation characterised by different types of thermal power fluctuations are investigated: electric arc furnace, billet reheating furnace and waste-to-energy plant. An interdisciplinary approach is adopted to face the crucial issues of developing a PCM-based technology (e.g. thermo-mechanical stresses, transient heat transfer). Chapter 1 includes the background, the motivation, the aim, the methodology and the structure of thesis. In chapter 2, a general overview on the thermal energy storage systems with a particular focus on latent heat storage systems based on PCMs is provided. Chapter 3 addresses the issues related to the energy recovery from the electric arc furnace and proposes three different configurations of a PCM-based device to increase the efficiency and the capacity factor of the downstream energy recovery system. In Chapter 4 an existing waste heat recovery system of a steel billet preheating furnace is retrofitted by adding a PCM-based device. In Chapter 5 a refractory brick technology based on PCMs is proposed for the protection of the radiant superheaters against high temperature corrosion and temperature fluctuations. At the end of each chapter a series of conclusions are reported, concerning the performed investigations and the obtained results

Development of Sustainable Masonry Brick

Implementation of environmentally-friendly and cost-effective building designs has been a persistent challenge to the civil engineering community. The current study aims to develop innovative masonry bricks which could open up the prospects in the future for inexpensive construction. It is also envisioned that if adopted, the proposed process of the brick fabrication could benefit the brick manufacturing industry by curtailing the carbon dioxide foot-print and firing energy levels without compromising the prescribed mechanical and physical properties of the resulting product. The research explores the potential of incorporating HBS-polymer which is a biologically-inert product produced after various treatment processes in the Environmental Laboratory of Lassonde, and Incinerated Sewage Sludge Ash (ISSA) obtained from biological treatment facilities as alternative raw materials in manufacturing low cost and environmentally-friendly masonry bricks. The development of geopolymer masonry bricks, that ensures minimum of 40% reuse of waste glass by weight per brick is an another actively pursued area of the current research. The geo-polymerization process was done using quarried shale, Recycled Crushed Glass (RCG) and sodium silicate. In contrast to the conventional masonry bricks fired exclusively over 1000 degree Celsius for no less than 24 hours, the geopolymer bricks were made at a firing temperature of 400 degree Celsius for four hours. In both cases the materials considered are used in partial replacement of shale, which in turn makes the geopolymer bricks and the Incinerated Sewage Sludge Ash bricks a potentially sustainable construction material in the sense that it uses wastes to replace the use of irreplaceable natural resources. The resulting hybrid bricks will be tested for the effect in compressive strength, flexural strength, split tensile strength, ultrasonic pulse velocity, cold as well as hot water absorption, saturation coefficient, efflorescence, freeze thaw damage, and resonant frequency, all being part of the established quality control procedures in this industry. For the HBS-polymer bricks, the findings indicate that, while the compressive strength, hot as well as cold water absorption and resistance to freeze-thaw damage of hybrid bricks was on par with the control brick without any shale replacement, HBS polymer bricks were much lighter (apparently owing to a better distribution of fine pores and without a commensurate increase in water absorption capacity). The results from the study of the Geo-polymer bricks, Bio-polymer bricks and SSA bricks suggest that they can be a promising solution for the long debated economical building construction with a reduced carbon footprint and firing energy while offering an alternative to landfill disposal of waste